Re: [PATCH REVIEW 2/2] tpm_tis: override durations for STM tpm with firmware 1.2.8.28

From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Alexey Klimov <aklimov@redhat.com>
Cc: linux-integrity@vger.kernel.org, jsnitsel@redhat.com,
	peterhuewe@gmx.de, jgg@ziepe.ca
Subject: Re: [PATCH REVIEW 2/2] tpm_tis: override durations for STM tpm with firmware 1.2.8.28
Date: Thu, 3 Jan 2019 15:14:53 +0200	[thread overview]
Message-ID: <20190103131453.GC10491@linux.intel.com> (raw)
In-Reply-To: <20181214132115.26223-2-aklimov@redhat.com>

On Fri, Dec 14, 2018 at 01:21:15PM +0000, Alexey Klimov wrote:
> There was revealed a bug in the STM TPM chipset used in Dell R415s.
> Bug is observed so far only on chipset firmware 1.2.8.28
> (1.2 TPM, device-id 0x0, rev-id 78). After some number of
> operations chipset hangs and stays in inconsistent state:
> 
> tpm_tis 00:09: Operation Timed out
> tpm_tis 00:09: tpm_transmit: tpm_send: error -5
> 
> Durations returned by the chip are the same like on other
> firmware revisions but apparently with specifically 1.2.8.28 fw
> durations should be reset to 2 minutes to enable tpm chip work
> properly. No working way of updating firmware was found.
> 
> This patch adds implementation of ->update_durations method
> that matches only STM devices with specific firmware version.
> 
> Cc: Jerry Snitselaar <jsnitsel@redhat.com>
> Signed-off-by: Alexey Klimov <aklimov@redhat.com>
> ---
>  drivers/char/tpm/tpm_tis_core.c | 90 +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 90 insertions(+)
> 
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index d2345d9fd7b5..e0bdca647460 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -514,6 +514,95 @@ static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len)
>  	return rc;
>  }
>  
> +struct tis_vendor_durations_override {
> +	u32 did_vid;
> +	struct tpm_version_t tpm_version;
> +	unsigned long durs[3];

I would rather have just "unsigned long durations[3];".

> +};
> +
> +static
> +const struct tis_vendor_durations_override vendor_dur_overrides[] = {
> +	/* STMicroelectronics 0x104a */
> +	{ 0x0000104A,
> +	{ 1, 2, 8, 28 },
> +	{ (2 * 60 * HZ), (2 * 60 * HZ), (2 * 60 * HZ) } },
> +};
> +
> +static bool tpm_tis_update_durations(struct tpm_chip *chip,
> +					unsigned long *duration_cap)
> +{
> +	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
> +	u32 did_vid;
> +	int i, rc;
> +	cap_t cap;
> +
> +	if (chip->ops->clk_enable != NULL)
> +		chip->ops->clk_enable(chip, true);
> +
> +	rc = tpm_tis_read32(priv, TPM_DID_VID(0), &did_vid);
> +	if (rc < 0)
> +		goto out;
> +
> +	for (i = 0; i != ARRAY_SIZE(vendor_dur_overrides); i++) {
> +		if (vendor_dur_overrides[i].did_vid != did_vid)
> +			continue;
> +
> +		/* Try to get a TPM version 1.2 TPM_CAP_VERSION_INFO */
> +		rc = tpm_getcap(chip, TPM_CAP_VERSION_1_2, &cap,
> +			"attempting to determine the 1.2 version",
> +			sizeof(cap.tpm_version_1_2));

Not properly aligned.

> +		if (!rc) {
> +			if ((cap.tpm_version_1_2.Major ==
> +				vendor_dur_overrides[i].tpm_version.Major) &&
> +				(cap.tpm_version_1_2.Minor ==
> +				vendor_dur_overrides[i].tpm_version.Minor) &&
> +				(cap.tpm_version_1_2.revMajor ==
> +				vendor_dur_overrides[i].tpm_version.revMajor) &&
> +				(cap.tpm_version_1_2.revMinor ==
> +				vendor_dur_overrides[i].tpm_version.revMinor)) {

Same.

> +
> +				memcpy(duration_cap,
> +					vendor_dur_overrides[i].durs,
> +					sizeof(vendor_dur_overrides[i].durs));

Same.

> +				rc = true;
> +				goto out;
> +			}
> +		} else {
> +			rc = tpm_getcap(chip, TPM_CAP_VERSION_1_1, &cap,
> +				"attempting to determine the 1.1 version",
> +				sizeof(cap.tpm_version));

Same.

> +			if (rc) {
> +				rc = false;
> +				goto out;
> +			}
> +			if ((cap.tpm_version.Major ==
> +				vendor_dur_overrides[i].tpm_version.Major) &&
> +				(cap.tpm_version.Minor ==
> +				vendor_dur_overrides[i].tpm_version.Minor) &&
> +				(cap.tpm_version.revMajor ==
> +				vendor_dur_overrides[i].tpm_version.revMajor) &&
> +				(cap.tpm_version.revMinor ==
> +				vendor_dur_overrides[i].tpm_version.revMinor)) {

Same.

> +
> +				memcpy(duration_cap,
> +					vendor_dur_overrides[i].durs,
> +					sizeof(vendor_dur_overrides[i].durs));

Same.

> +				rc = true;
> +				goto out;
> +			}
> +		}
> +	}
> +
> +	rc = false;

Shoud return proper rc instead of bool. 

> +
> +out:
> +	if (chip->ops->clk_enable != NULL)
> +		chip->ops->clk_enable(chip, false);
> +
> +	return rc;
> +}
> +
> +
>  struct tis_vendor_timeout_override {
>  	u32 did_vid;
>  	unsigned long timeout_us[4];
> @@ -847,6 +936,7 @@ static const struct tpm_class_ops tpm_tis = {
>  	.send = tpm_tis_send,
>  	.cancel = tpm_tis_ready,
>  	.update_timeouts = tpm_tis_update_timeouts,
> +	.update_durations = tpm_tis_update_durations,
>  	.req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
>  	.req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
>  	.req_canceled = tpm_tis_req_canceled,
> -- 
> 2.14.4
> 

/Jarkko